System and method for error checking of failed I/O open calls

ABSTRACT

A system and method in a data processing system for error checking and resolving failed input/output open calls. A configuration mechanism configures the options, such as the information stored in databases, details of how each error check is performed, and what actions should be taken when improper error checking occurs. Based on data stored in databases, such as an I/O calls database, a rules with syntax database, and an usage calls database, an error check of a failed input/output open call is performed.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention relates generally to an improved data processingsystem and, in particular, to a method, system and computer programproduct for optimizing performance in a data processing system. Stillmore particularly, the present invention provides a method, system, andcomputer program product to ensure software quality through errorchecking and resolving failed input/output open calls.

2. Description of Related Art

Failure to ensure software quality can jeopardize a company'sreputation, as well as cause significant profit loss. Poor softwarequality can be a result of poor error checking. For example, a softwareprogram accesses an external device, such as reading a hard disk, butfails to check the access request for errors. Since software todaycompletes ample Input and Output (I/O) manipulations, an area of errorchecking that can increase software quality is failed I/O open calls. Anexample of an I/O open call is “open(x),” where “x” is a hardware devicethat the software code is accessing, or opening, so that subsequentsoftware code can read data from the hardware device. If an I/O opencall fails and subsequent software code uses the return value, or data,without properly handling error cases, the software code could haveerratic or unintended behavior. Tools exist today that check for ignoredreturn values. However, these tools only provide reporting mechanisms,but no resolutions.

Therefore, it would be advantageous to have a method, system, andcomputer program product to ensure software quality through errorchecking and resolving failed Input/Output open calls.

SUMMARY OF THE INVENTION

The present invention provides a method, system, and computer programproduct for ensuring software quality through error checking andresolving of failed input/output open calls. A configuration mechanismconfigures the options, such as the information stored in databases,details of how each error check is performed, and what actions should betaken when improper error checking occurs. Based on data stored indatabases, such as an I/O calls database, a rules with syntax database,and an usage calls database, a code analyzer analyzes code in softwareprograms for an error check of a failed input/output open call. Areporting mechanism reports data from the analyzed code to a reportfile, such as why software programs have proper and impropererror-checking instances, sends errors from the analyzed code to anerror file, and enables these files to be displayed on a display.Finally, the code analyzer enables resolving an improper error check forthe failed input/output open call.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features believed characteristic of the invention are setforth in the appended claims. The invention itself, however, as well asa preferred mode of use, further objectives and advantages thereof, willbest be understood by reference to the following detailed description ofan illustrative embodiment when read in conjunction with theaccompanying drawings, wherein:

FIG. 1 is a pictorial representation of a data processing system inwhich the present invention may be implemented in accordance with apreferred embodiment of the present invention;

FIG. 2 is a block diagram of a data processing system that may beimplemented as a server, is depicted in accordance with a preferredembodiment of the present invention;

FIG. 3 is a block diagram illustrating a data processing system isdepicted in which the present invention may be implemented;

FIG. 4 is a block diagram of the components for error checking andresolving failed input/output open calls, according to a preferredembodiment of the present invention;

FIG. 5 is an example of the I/O open calls found in the I/O open callsdatabase for error checking and resolving failed input/output opencalls, according to a preferred embodiment of the present invention;

FIG. 6 is an example of the rules with syntax found in the rules withsyntax database for error checking and resolving failed input/outputopen calls, according to a preferred embodiment of the presentinvention; and

FIG. 7 is an example of the usage calls in the usage calls database forerror checking and resolving failed input/output open calls, accordingto a preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

With reference now to the figures, FIG. 1 depicts a pictorialrepresentation of a network of data processing systems in which thepresent invention may be implemented. Network data processing system 100is a network of computers in which the present invention may beimplemented. Network data processing system 100 contains a network 102,which is the medium used to provide communications links between variousdevices and computers connected together within network data processingsystem 100. Network 102 may include connections, such as wire, wirelesscommunication links, or fiber optic cables.

In the depicted example, server 104 is connected to network 102 alongwith storage unit 106. In addition, clients 108, 110, and 112 areconnected to network 102. These clients 108, 110, and 112 may be, forexample, personal computers or network computers. In the depictedexample, server 104 provides data, such as boot files, operating systemimages, and applications to clients 108-112. Clients 108, 110, and 112are clients to server 104. Network data processing system 100 mayinclude additional servers, clients, and other devices not shown. In thedepicted example, network data processing system 100 is the Internetwith network 102 representing a worldwide collection of networks andgateways that use the Transmission Control Protocol/Internet Protocol(TCP/IP) suite of protocols to communicate with one another. At theheart of the Internet is a backbone of high-speed data communicationlines between major nodes or host computers, consisting of thousands ofcommercial, government, educational and other computer systems thatroute data and messages. Of course, network data processing system 100also may be implemented as a number of different types of networks, suchas for example, an intranet, a local area network (LAN), or a wide areanetwork (WAN). FIG. 1 is intended as an example, and not as anarchitectural limitation for the present invention.

Referring to FIG. 2, a block diagram of a data processing system thatmay be implemented as a server, such as server 104 in FIG. 1, isdepicted in accordance with a preferred embodiment of the presentinvention. Data processing system 200 may be a symmetric multiprocessor(SMP) system including a plurality of processors 202 and 204 connectedto system bus 206. Alternatively, a single processor system may beemployed. Also connected to system bus 206 is memory controller/cache208, which provides an interface to local memory 209. I/O Bus Bridge 210is connected to system bus 206 and provides an interface to I/O bus 212.Memory controller/cache 208 and I/O Bus Bridge 210 may be integrated asdepicted.

Peripheral component interconnect (PCI) bus bridge 214 connected to I/Obus 212 provides an interface to PCI local bus 216. A number of modemsmay be connected to PCI local bus 216. Typical PCI bus implementationswill support four PCI expansion slots or add-in connectors.Communications links to clients 108-112 in FIG. 1 may be providedthrough modem 218 and network adapter 220 connected to PCI local bus 216through add-in connectors.

Additional PCI bus bridges 222 and 224 provide interfaces for additionalPCI local buses 226 and 228, from which additional modems or networkadapters may be supported. In this manner, data processing system 200allows connections to multiple network computers. A memory-mappedgraphics adapter 230 and hard disk 232 may also be connected to I/O bus212 as depicted, either directly or indirectly.

Those of ordinary skill in the art will appreciate that the hardwaredepicted in FIG. 2 may vary. For example, other peripheral devices, suchas optical disk drives and the like, also may be used in addition to orin place of the hardware depicted. The depicted example is not meant toimply architectural limitations with respect to the present invention.

The data processing system depicted in FIG. 2 may be, for example, anIBM eServer pSeries system, a product of International Business MachinesCorporation in Armonk, N.Y., running the Advanced Interactive Executive(AIX) operating system or LINUX operating system.

With reference now to FIG. 3, a block diagram illustrating a dataprocessing system is depicted in which the present invention may beimplemented. Data processing system 300 is an example of a clientcomputer. Data processing system 300 employs a peripheral componentinterconnect (PCI) local bus architecture. Although the depicted exampleemploys a PCI bus, other bus architectures such as Accelerated GraphicsPort (AGP) and Industry Standard Architecture (ISA) may be used.Processor 302 and main memory 304 are connected to PCI local bus 306through PCI Bridge 308. PCI Bridge 308 also may include an integratedmemory controller and cache memory for processor 302. Additionalconnections to PCI local bus 306 may be made through direct componentinterconnection or through add-in boards. In the depicted example, localarea network (LAN) adapter 310, small computer system interface (SCSI)host bus adapter 312, and expansion bus interface 314 are connected toPCI local bus 306 by direct component connection. In contrast, audioadapter 316, graphics adapter 318, and audio/video adapter 319 areconnected to PCI local bus 306 by add-in boards inserted into expansionslots. Expansion bus interface 314 provides a connection for a keyboardand mouse adapter 320, modem 322, and additional memory 324. SCSI hostbus adapter 312 provides a connection for hard disk drive 326, tapedrive 328, and CD-ROM drive 330. Typical PCI local bus implementationswill support three or four PCI expansion slots or add-in connectors.

An operating system runs on processor 302 and is used to coordinate andprovide control of various components within data processing system 300in FIG. 3. The operating system may be a commercially availableoperating system, such as Windows XP, which is available from MicrosoftCorporation. An object oriented programming system such as Java may runin conjunction with the operating system and provide calls to theoperating system from Java programs or applications executing on dataprocessing system 300. “Java” is a trademark of Sun Microsystems, Inc.Instructions for the operating system, the object-oriented programmingsystem, and applications or programs are located on storage devices,such as hard disk drive 326, and may be loaded into main memory 304 forexecution by processor 302.

Those of ordinary skill in the art will appreciate that the hardware inFIG. 3 may vary depending on the implementation. Other internal hardwareor peripheral devices, such as flash read-only memory (ROM), equivalentnonvolatile memory, or optical disk drives and the like, may be used inaddition to or in place of the hardware depicted in FIG. 3. Also, theprocesses of the present invention may be applied to a multiprocessordata processing system.

As another example, data processing system 300 may be a stand-alonesystem configured to be bootable without relying on some type of networkcommunication interfaces As a further example, data processing system300 may be a personal digital assistant (PDA) device, which isconfigured with ROM and/or flash ROM in order to provide non-volatilememory for storing operating system files and/or user-generated data.

The depicted example in FIG. 3 and above-described examples are notmeant to imply architectural limitations. For example, data processingsystem 300 also may be a notebook computer or hand held computer inaddition to taking the form of a PDA. Data processing system 300 alsomay be a kiosk or a Web appliance.

The present invention provides a system and method for error checkingand resolving failed input/output (I/O) open calls. The inventioninvolves examining software programs (in C, C++, Java, etc.) stored on aserver for specific I/O open calls, checking that the software codeproperly handles error cases of the return values for the I/O open callsbefore proceeding to use those return values, and providing resolutionsfor failed I/O open calls. Typically current solutions only check to seeif return values from I/O open calls have been used, but do not ensurethat software developers have properly checked and resolved error casesprior to using the return values. This invention takes further measuresto ensure that the proper error checking is in place, and providesresolution for improper checking, which prevents erratic andunintentional code behavior, thereby increasing software quality.

FIG. 4 is a block diagram of the components for error checking andresolving failed input/output open calls, according to a preferredembodiment of the present invention, which may be implemented usingcomponents of a data processing system, such as data processing system300 in FIG. 3. Code analyzer 400 examines a set of software programs onserver 402 for proper error checking of failed I/O open calls, where theset of software programs is comprised of one or more software programs.Code analyzer 400 is able to interpret software programs implemented inany software programming language and able to examine software programson any type of server. Code analyzer 400 checks software programs basedon data stored in set of databases, which includes one or more database.Examples of databases include I/O calls database 404, rules with syntaxdatabase 406, and usage calls database 408. The options for codeanalyzer 400 are configured by the user through configuration mechanism410, such as details of how each error check is performed and whatactions should be taken when improper error checking occurs. Codeanalyzer 400 sends data about what to report to report mechanism 412,such that report mechanism 412 reports any data to report file 414 andreports any errors that occur during execution to error file 416. Thenthe user can access report file 414 and error file 416 directly throughdisplay 418, which can be a terminal screen, PDA, etc., or throughe-mail.

Code analyzer 400 has a resolution feature that allows users to specifyvia configuration mechanism 410 what actions should be taken whenimproper error checking occurs. This feature enables code analyzer 400to automatically resolve improper error checking. For example, the I/Oopen call, such as open from I/O database 404, has a number ofdocumented error conditions. Code analyzer 400 checks that each errorcondition of the I/O call has been properly checked prior to furtherusage (such as “fread” from usage calls database 408). The featureprovides resolutions such as flagging or highlighting the improper errorchecking code, displaying the correct error checking code, etc., asspecified by the user through configuration mechanism 410.

Code analyzer 400 can also enable error checking and resolving failedI/O open calls on development tool 420, a software tool that is used tohelp user's development code, such as Eclipse, VisualAge, WebSphere,etc. Development tool 420 is used with development tool plug-in 422, toenable the various features of this invention. Development plug-in 422can be used to examine software programs developed using developmenttool 420. Development tool plug-in 422 automatically resolves impropererror checking in real-time. Real-time means that as a user codes asoftware program, development tool 420 is able to flag or highlightimproper handling or error cases, development tool 420 reports theseresults as configured, and the development tool plug-in's configurableresolutions take place as improper error checking occurs.

For example, a particular open call has five error cases. As soon as theuser types “ . . . open . . . ” (for example, “fd=open( )”), the I/Oopen call may be flagged or highlighted in a distinct color, where theuser specifies the color as a configurable feature. This color signifiesthat a match has been found in I/O open calls database 404. If the usertypes “ . . . fread . . . ”, which has a match in usage calls database408, before doing proper error-checking as specified in rules setsdatabase 406, the resolution feature automatically displays a switchstatement covering each error case that was either not checked orimproperly checked. The user cannot continue coding until afterselecting the options displayed by development tool 420 through display418, in order to handle each error case that was either not checked orimproperly checked.

Configuration mechanism 410 allows the user to configure a set of typesof the set of software programs in server 402 or development tool 420that the user would like to check, such as C and C++ programs only,etc., whereby the set of types includes one or more types. The user usesconfiguration mechanism 410 to specify the interval or frequency inwhich he would like the software programs in server 402 to be examinedor checked. Additionally, the user uses configuration mechanism 410 tospecify the information stored in databases, such as I/O open callsdatabase 404, rules sets database 406, and usage calls database 408.Furthermore, configuration mechanism 410 specifies the format of outputto display 418. Other specifications selected by configuration mechanism410 include where report mechanism 412 sends reports and errors, such asto e-mail or display 418, what errors report mechanism 412 sends toerror file 416, and what reports report mechanism 412 sends to reportfile 414. Furthermore, configuration mechanism 410 allows the user tospecify to code analyzer 400 what to do when a software program hasimproper error checking, details of how each error check is performed(such as when it is executed), the collection of a set of operationalstatistics for the set of software programs (such as the number andcauses of improper error checking, an estimation of the percentage ofsoftware quality, and so on), etc., whereby the set of operationalstatistics contains one or more statistics. These specifications allowthe user to completely tailor the entire process of how softwareprograms are checked. The set of the options selected by the user inconfiguration mechanism 410 includes one or more options, and are sentto code analyzer 400.

I/O open calls database 404 stores a set of I/O open calls (such asopen, fopen, etc.) that should be searched for in software programs inserver 402 or development tool 420, whereby the set of I/O open callsincludes one or more I/O open calls. Typically, these I/O calls willreturn a non-zero integer upon success and a negative one (−1) onfailure, or a FILE* upon success and a NULL upon failure. The user canupdate I/O open calls database 404 as needed through configurationmechanism 410 via code analyzer 400. The user can opt to have I/O opencalls database 404 pre-loaded with a pre-determined set of I/O opencalls. FIG. 5 is an example of the I/O open calls found in I/O opencalls database 404 for error checking and resolving failed input/outputopen calls, according to a preferred embodiment of the presentinvention.

Rules with syntax database 406 stores a set of rules with syntax (suchas while (fd!=−1), etc.) that should be searched for in softwareprograms in server 402 or development tool 420, whereby the set of ruleswith syntax includes one or more rules with syntax. The user can updaterules with syntax database 406 as needed through configuration mechanism410 via code analyzer 400. The user can opt to have rules with syntaxdatabase 406 pre-loaded with a pre-determined set of syntax-matchingrules. FIG. 6 is an example of the rules with syntax found in rules withsyntax database 406 for error checking and resolving failed input/outputopen calls, according to a preferred embodiment of the presentinvention.

Usage calls database 408 stores a set of usage calls (such as read,write, etc.) that should be searched for in software programs in server402 or development tool 420 in which the return values from the I/O opencalls stored in I/O open calls database 404 are used, whereby the set ofusage calls includes one or more usage calls. The user can update usagecalls database 408 as needed through configuration mechanism 410 viacode analyzer 400. The user can opt to have usage calls database 408pre-loaded with a pre-determined set of usage calls. FIG. 7 is anexample of the usage calls in usage calls database 408 for errorchecking and resolving failed input/output open calls, according to apreferred embodiment of the present invention.

Report mechanism 412 reports proper and improper error checking. Theseresults are sent to report file 414 and error file 416. The user canconfigure report mechanism 412 through configuration mechanism 410 toreport additional information such as why software programs have properand improper error-checking instances, as well as where to correct oradd error-checking and resolutions, etc. This provides evidence on howproperly software programs handle error checking or ensure softwarequality.

Server 402 is where the software programs reside to be checked by codeanalyzer 400. Server 402 can be of any type (i.e., Linux, Windows, AIX,etc.) or any configuration. The software programs that reside on server402 can be in any software programming language (i.e. C, C++, Java,etc.). Server 402 returns requested data to code analyzer 400 in orderto determine whether the error-checking for failed I/O open calls isproper.

Altogether, the method and system of the present invention describedabove provides error-checking and resolutions for failed input/outputopen calls.

It is important to note that while the present invention has beendescribed in the context of a fully functioning data processing system,those of ordinary skill in the art will appreciate that the processes ofthe present invention are capable of being distributed in the form of acomputer readable medium of instructions and a variety of forms and thatthe present invention applies equally regardless of the particular typeof signal bearing media actually used to carry out the distribution.Examples of computer readable media include recordable-type media, suchas a floppy disk, a hard disk drive, a RAM, CD-ROMs, DVD-ROMs, andtransmission-type media, such as digital and analog communicationslinks, wired or wireless communications links using transmission forms,such as, for example, radio frequency and light wave transmissions. Thecomputer readable media may take the form of coded formats that aredecoded for actual use in a particular data processing system.

The description of the present invention has been presented for purposesof illustration and description, and is not intended to be exhaustive orlimited to the invention in the form disclosed. Many modifications andvariations will be apparent to those of ordinary skill in the art. Theembodiment was chosen and described in order to best explain theprinciples of the invention, the practical application, and to enableothers of ordinary skill in the art to understand the invention forvarious embodiments with various modifications as are suited to theparticular use contemplated.

1. A computer-implemented method for error checking and resolving failedinput/output open calls, the method comprising: configuring a set ofmethod options, the set of configured method options including: a set oftypes of the set of programs to error check, a type of error check to beperformed, a frequency for the set of programs to be error checked, aset of operational statistics for the set of programs, where the data isreported and the errors that are sent, the errors sent to an error file,the data reported to a report file, an output format for a display, aresolution for an improper error check for a failed input/output opencall; analyzing data in a set of programs for an error check of a failedinput/output open call, based on data stored in a set of databases, theset of databases including a rules with syntax database, an input/outputopen calls database, and a usage calls database. wherein the rules withsyntax database stores a set of rules with syntax and is preloaded witha pre-determined set of syntax matching rules, the input/output opencalls database stores a set of I/O open calls and is pre-loaded with apre-determined set of input/output open calls, and the usage callsdatabase stores a set of usage calls and is preloaded with apre-determined set of usage calls; reporting data from the analyzed datain the set of programs to a report file, the reported data includinginformation regarding the set of programs having an improper error checkand a location for an error checking instance and resolution; sending anerror from the analyzed data to an error file; displaying a file on adisplay; resolving an improper error check for the failed input/outputopen call; and forwarding the set of method options to a softwaredevelopment tool plug-in to examine and resolve a set of programsdeveloped using a software development tool in real time.
 2. A dataprocessing system for error checking and resolving failed input/outputopen calls, the data processing system comprising a processor and amemory communicatively coupled to the processor, the memory storinginstructions comprising: configuring means for configuring a set of dataprocessing system options, the set of configured data processing systemoptions including: a set of types of the set of programs to error check,a type of error check to be performed, a frequency for the set ofprograms to be error checked, a set of operational statistics for theset of programs, where the data is reported and the errors that aresent, the errors sent to an error file, the data reported to a reportfile, an output format for a display, a resolution for an improper errorcheck for a failed input/output open call; analyzing means for analyzingdata in a set of programs for an error check of a failed input/outputopen call, based on data stored in a set of databases, the set ofdatabases including a rules with syntax database, an input/output opencalls database, and a usage calls database, wherein the rules withsyntax database stores a set of rules with syntax and is preloaded witha pre-determined set of syntax matching rules, the input/output opencalls database stores a set of I/O open calls and is pre-loaded with apre-determined set of input/output open calls and the usage callsdatabase stores a set of usage calls and is preloaded with apre-determined set of usage calls; reporting means for reporting datafrom the analyzed data in the set of programs to a report file, thereported data including information regarding the set of programs havingan improper error check and a location for an error checking instanceand resolution; sending means for sending an error from the analyzeddata to an error file; displaying means for displaying a file on adisplay; resolving means for resolving an improper error check for thefailed input/output open call; and forwarding means for forwarding dataprocessing system options to a software development tool plug-in toexamine and resolve a set of programs developed using a softwaredevelopment tool in real time.
 3. A computer program product comprisinga computer-recordable medium including instructions embodied thereon,which when executed, perform error checking and resolving of failedinput/output open calls, the computer program product comprising: firstinstructions for configuring a set of computer program product options,the set of configured data processing system options including: a set oftypes of the set of programs to error check, a type of error check to beperformed, a frequency for the set of programs to be error checked, aset of operational statistics for the set of programs, where the data isreported and the errors that are sent, the errors sent to an error file,the data reported to a report file, an output format for a display, aresolution for an improper error check for a failed input/output opencall; second instructions for analyzing data in a set of programs for anerror check of a failed input/output open call, based on data stored ina set databases, the set of databases including a rules with syntaxdatabase, an input/output open calls database, and a usage callsdatabase, wherein the rules with syntax database stores a set of ruleswith syntax and is preloaded with a pre-determined set of syntaxmatching rules, the input/output open calls database stores a set of I/Oopen calls and is pre-loaded with a pre-determined set of input/outputopen calls, and the usage calls database stores a set of usage calls andis pre-loaded with a pre-determined set of usage calls; thirdinstructions for reporting data from the analyzed data in the set ofprograms to a report file; fourth instructions for sending an error fromthe analyzed data to an error file; fifth instructions for displaying afile on a display; sixth instructions for resolving an improper errorcheck for the failed input/output open call; and seventh instructionsfor forwarding computer program product options to a softwaredevelopment tool plug-in to examine and resolve a set of programsdeveloped using a software development tool in real time.